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suggestions for filling holes in clear acrylic

Posted: Oct 17th, '11, 17:46
by jspiezio
I have a curved acrylic shield that cracked a bit when my guys were drilling holes through it. I need to fill the holes and I am hoping one of the experts on here has been through a similar scenario.

Any pointers?

Posted: Oct 17th, '11, 18:13
by Raybo Marine NY
there is a specific adhesive for it, if you have a plastics guy close by maybe get some from him or just ask him to glue it up for you

Posted: Oct 17th, '11, 18:15
by tunawish
Hey John,

Break a coolant shield on one of the Matsuura's...???

Ray

Posted: Oct 17th, '11, 21:29
by jspiezio
there is a specific adhesive for it, if you have a plastics guy close by maybe get some from him or just ask him to glue it up for you
Any suggestions here on LI?


Break a coolant shield on one of the Matsuura's...???

Ray
I wish it was that simple.



Okay, this is part of a large assembly for a new Canadian anti-submarine helicopter. This is called the "splash guard", it is a 4 foot tall by 2 foot diameter sealed "tube" that the sonar buoy rests in after being pulled up through the hull. It keeps all the salt water contained.

Two halves of curved acrylic assembled to all sorts of metal parts and plastic re-enforcers. One little mess up and now the full assembly is in jeopardy, meanwhile Sikorsky is yelling at me for the thing.

Posted: Oct 17th, '11, 23:37
by In Memory Walter K
I was going to suggest a delicately placed drop of acetone placed at the base of the drilled hole with the fine crack coming from it. The capillary action would run it into the length of the crack and "weld" the two together. Given the importance of what you are doing, I hesitate to suggest it. You be the judge. Also, consider going to one of those "invisible" windshield repair guys that seem to do miracles on fine windshield chips and hairline breaks and see what they have to suggest. Walter

Posted: Oct 18th, '11, 06:11
by Raybo Marine NY
I didnt even notice your location.
Try Marine Plastics in West Babylon , used to be Descon

Posted: Oct 18th, '11, 06:14
by CaptPatrick
The correct and only welding solvent for acrylic is Methylene Chloride, commonly refered to as MEC.

For plugging holes, the plug has to exactly match the hole. As Walter said, capillary action will draw the solvent in, but only MEC will effect the weld.

Cracking and chipping due to drilling usually comes from using the wrong type of drill bit. See: ---- Drilling Acrylic ----

Posted: Oct 18th, '11, 07:02
by CaptPatrick
John,

If the hole to be plugged is round, carefully tap it and clean the threads soap and water then rinse well. Machine a dowel from the same acrylic and thread to match the tapped hole. Clean as above.

Screw the threaded rod onto the hole, apply the MEC with a dropper or syringe, allow 15 minutes for the solvent to fully evaporate before proceeding. Cut the excess rod, wet sand the surface through 2000 grit paper and polish with a plastic polish.

Novus is one brand of plastic polish, but I use, and by far, prefer the polishing supplies produced by Micro-Surface Finishing Products, Inc.

Posted: Oct 18th, '11, 07:57
by jspiezio
Thank you everyone of you.

I have a call into Marine Plastics now, and if that fails I will proceed as Capt P and Walter suggest.

Posted: Oct 18th, '11, 08:23
by randall
thanks for the link patrick.....i have all these acrylic boxes that need resto.

i use em as display cases for art fairs. people for some reason think a sign that says "do not touch" means everyone in the world but them!

Posted: Oct 18th, '11, 09:52
by Rawleigh
I remember in high school (a long time ago) going on a field trip to Carolina Biological supply and watching them make the acrylic tube displays for the preserved specimens as Capt. Pa says. They use clear tubes with colored pieces of flat acrylic cut in squares as ends. They put the tube down on the flat piece and used a needle to put a drop of MEC at the joint. The capillary action pulled in into the joint and welded it together. I never could remember what the chemical was until Pat just told me. Where do you buy some? I have MEK, but not MEC.

Posted: Oct 18th, '11, 10:14
by CaptPatrick
Where do you buy some?
Methylene Chloride from US Plastics



.

Posted: Oct 18th, '11, 14:21
by Rawleigh
I have about a 2" long crack in my flybridge windshield emanating from one of the bolts. Is it acrylic? Do you think this would help it or just make a mess?

Posted: Oct 18th, '11, 15:36
by Raybo Marine NY
jspiezio wrote:Thank you everyone of you.

I have a call into Marine Plastics now, and if that fails I will proceed as Capt P and Walter suggest.
sometimes takes more then 1 call

Posted: Oct 18th, '11, 18:48
by randall
i broke the windshield on the 25 in half and repaired it with some plexi glue i got on line. lasted years no problem.